In a study of 11 healthy men ages more than 5 y given 2 mg/night of GHRH 1-29 s.c. nightly for 6 weeks measures of phosphocreatine/phosphate ratios and intracellular pH by MRI spectroscopy were consistent with a GHRH treatment effect to reduce the need for anaerobic metabolism during exercise. In a study of GH and sex steroid administration for 6 months, baseline data from 53 healthy women and men more than 65y suggest that there are differing relationships of spontaneous GH and cortisol secretion with one another and with body fat, lean mass, and strength in men vs. women. Thus, (1) GH and cortisol appear to exert gender-specific effects on cardiovascular risk factors, and (2) endogenous cortisol secretion may be related to the declines in strength and mobility which occur in healthy elderly women.